[WordPress] Dynamic Dropdown lists for Categories, Sub-Categories, Posts!

Greetings people!

This is my first post for this forum so I would like to wish you all a Happy New Year!

I’m using WordPress 3.5 as CMS to develop my personal website.

The reason I’m writting, is that I need a way to implement a code or plugin to allow users to navigate through posts using dependent(chained) dropdown lists.

In other words I would like 3 dropdown menus to be dynamically populated based on the selection chosen in the previous dropdown lists.

This would consist of:

Dropdown 1: Category *
Dropdown 2: Sub- Category *
Dropdown 3: List of posts in Sub-Category *

*Dropdown 1 would be pre populated with categories.
*Dropdown 2 would list the sub categories of menu 1 based on the user selection.
*Dropdown 3 would list the posts in the sub category chosen in menu 2.

To help you understand further, in my website I have the Category “TV Series” which has as sub-categories(child) other series, like “Dexter”, “CSI:Miami” etc.
Series also have other sub-categories(child) the number of seasons, like “Season 1” “Season 2” “Season N”. Each season contains the appropriate posts.

The Hierarchy is like this:

Tv Series

–Season 1
–Season 2
–Season n

–Season 1
–Season 2
–Season n

So for example the dynamic dropdowns I would like to use are the following:

Dropdown 1: Select TV Show (Category)
Dropdown 2: Select Season (sub-category)
Dropdown 3: Select Episode (posts)

I would really appreciate if you could help me with the matter as I was searching the web for the past few days without any results.

Thanks in advance.

For the first dopdown you can use get_categories, for the second level use same function adding [I]parent[/I] parameter to the arguments. If you don’t want to deal with outputting html yourself, then [URL=“http://codex.wordpress.org/Function_Reference/wp_dropdown_categories”]wp_dropdown_categories might be more suitable.
To get posts get_posts seems suitable with added category parameter to arguments array.

If you’re not coding the theme, and it’s pre-built, you can easily achieve all this with Gravity Forms; it’s a premium plug-in but as mentioned by many, well worth your dollars.